Lord of Darkness
by AngryBandit59
Summary: Finn meets a mysterious man in a black suit, and after a brief fight with him, the hero discovers he has a terrifying new dark powers... Will he fall for the ways of evil, or will Marceline show him that just because you're a monster doesn't make you evil? ( a Finnceline fic)
1. Prolouge

A man in a black suit stood in a tree, looking down at a sobbing baby in the middle of a dirt path. A frown spread across his lips as he pulled a small canteen of whiskey out of his jacket, taking a sip.

The man had a pointed nose, slicked back, oily brown hair, and strange, almost glowing yellow pupils. But, compared to most inhabits of Earth at that day and age, he looked shockingly human.

"Do you really think that wailing, tubby little baby could be a possible candidate, Death?" asked the man to a robed figure with a horse-skull for a head, floating right next to him.

"I'm not sure... I can sense a dark energy inside him, but it's dismal at best. Not only that, he's human. Those things were pathetic, and the reason we're doing all this in the first place!" said Death, robed flapping in the breeze.

The man in the suit put his alcohol back in his coat pocket, "I know. So, should we pop the little sucker?"

Death shook his head, "No. If we kill him, and on the off chance he is who we're looking for, then we'll have to wait for another thousand years. Just let him live. If he does have more power locked away somewhere, then he'll be able to survive out here... and if he does, then we'll see if he meets the requirements."

The man in the suit laughed a bit, "Death, look. Those two bulldogs down there are talking about adopting him."

Death looked down, seeing that what his comrade had said was true, "Yes, they are. Anyway, let's keep rounding up more likely candidates."

With that, Death extended his long, sharp finger and ripped a hole in the fabric of space, creating a glowing blue portal. He flew into it, followed by the man in the suit.


	2. Chapter 1: Talix

**Props to whoever guesses which game this fic was loosely based off of!**

* * *

Finn walked along the path, snickering to himself, unable to control his excitement. Today was the day he and Marceline were going to go explore that new dungeon he discovered!

His thoughts drifted to the pale vamp. Her beautiful smile, her long, raven hair, her angelic singing voice, her enticing laugh... her shapely hips...

Finn nearly slapped himself in the face. Why was he thinking about his best friend like that? He entered the forest, continuing to trek towards where he and Marcy had agreed to meet.

As soon as he stepped into the shadows cast by the tree tops, he heard a venomous, yet smooth voice behind him,"Hello, Finn. It's been a while."

There, stepping out from behind a tree, was a pasty skinned man with slicked back chestnut brown hair. He wore a crisp, tie-less, casual black suit with the top two buttons undone. His yellow pupils seemed to glow in the shade of the forest.

Finn gasped, "Are- are you a human!?"

The man smiled and gingerly shook his head no, "Sorry, kid. By the way, you don't know who I am, do you?"

Finn sighed, hoping he had at last met another full blooded human,"Never seen you before in my life..."

The man extended his hand, giving Finn a firm handshake, "The names Talix. And you better thank your lucky stars, kid! Because me and my partner have chosen you to be as a candidate."

Finn tilted his head, confused, "A candidate? For what?"

Talix smiled, "If you live, then you'll know soon enough."

The words hit Finn like a locomotive.

'_He's going to try and kill me!'_ he thought to himself, right before he leaned back his head to avoid a slash from Talix's knife.

Finn drew his father's sword, swinging it at the mysterious man. With a chuckle, Talix blocked his attack with his knife. Finn's mouth formed an 'O' in surprise.

Talix then forced Finn's sword out of his hand, and took a stab at him with the knife. Finn caught his wrists, however, and they wrestled over the knife.

"What the cabbage, man? What have I ever done to you?" said Finn through gritted teeth.

Talix chuckled darkly, "I'm just trying to help you, Finn! Now, show me some of that dark power!"

With that, Talix lifted one hand from his knife and the palm began to glow purple with energy. Finn's eyes went wide as that energy went off, charring the hero's chest and forcing him against a tree.

Talix strode over to Finn and frowned, "Come on... you've killed countless amounts of monsters... and beat the Lich! You MUST have some power sleeping within you!"

Finn grimaced, blood dripping from his bottom lip, "I don't have any powers..."

Talix smiled sadistically, "If you haven't even discovered them yet... then your power must be larger then Death and I realized... here, allow me to bless you with your true nature!"

With that, the man picked Finn up off the ground, Finn kicking at his face, but to no affect. He forced Finn face first into the ground, then thrust a finger knuckled deep into his mid-back, the digit penetrating his flesh. Finn cried out in white-hot agony. It felt as though someone had stuck an hot iron rod into his spine, and deadly electricity was flowing through him.

Suddenly, Finn put his face back into the soddy, leave covered ground of the forest, his whole body, especially his back, beginning to feel numb.

Talix pulled his bloody finger out of the hero's back and leaned over him, putting a hand in his bear hat and stroking his flowing, golden locks, "Don't worry, Finn... after you come to, your power shall awaken... well, I must be going. Don't worry, my friend, I'll be keeping a close eye on you!" he whispered into the human's ear.

The man pulled his hand out of Finn's hair and began walking off.

Talix began walking away, lifting his arm into the air and saying, "Adios!"

Then the hero's body lost all feeling as his vision blurred, and he finally passed out.


	3. Chapter 2: Tattoo

Marceline huffed, sitting in a tree branch. Where was Finn? He was usually so punctual...

She sighed, fiddling with her long yellow gloves she wore to protect herself from the sun. Her thoughts drifted to the blond hero... ever since he turned 16 a few days ago, she was starting to have... thoughts about him.

She waited a few more minutes before huffing.

"Where is he?!" she yelled suddenly.

"Who?" asked a voice from behind her.

She spun around, seeing a man in a dark suit floating behind her. "H-how did you sneak up on me?"

The man chuckled, "You Vampires are too damned full of yourselves. It wasn't that hard, really. By the way, if you're waiting for your boyfriend, Finn, he should be down the path... taking a little nap..."

Her eyes turned completely red, "YOU BASTARD! WHAT DID YOU DO TO HIM!?"

The man chuckled, "Don't worry, I just knocked him out. But you better enjoy him while he lasts, because he's not going to be a hero for much longer..."

She swung her ax-bass at him, but the deadly instrument came to a halt when the man caught it in between his fingers.

He chuckled, wagging his finger right in front of her face. "Temper temper! Now, as much as I'd like to play with you, I do have better things to do."

With that, the man grabbed her hand and chucked her into a nearby tree. Marceline quickly caught herself and floated above ground, but she saw no sign of the man anywhere.

She gasped, '_Finn!'_

She then flew down the path the man pointed out, not caring whether or not it was a trap.

* * *

Finn opened his eyes, first noticing he was shirtless in a purple sheeted bed. Second thing, Marceline was asleep next to him, snuggling into his side.

He felt all warm inside, a vivid blush spreading across his cheeks. He liked having the pale girl at his side.

'_Am I in love with her?'_ he thought to himself. '_Urgh- I don't have time for pondering about my love life! I just got my ass kicked by some weirdo.'_

He gently shook Marceline awake. Her red eyes peeked open, and she gave him a bear hug, "Oh, Finn! I was worried sick about you!"

Finn smiled, returning the hug. "Thanks, Marcy. Hey, why am I in your bed?"

She blushed, "Oh... sorry. I didn't want to put you on my uncomfortable couch. But what happened to you anyway?"

He rubbed his temples, "Some weirdo named Talix totally destroyed me..."

Her eyes narrowed, "Did he have brown hair, yellow eyes, and was wearing a black suit?"

He shook his head. Marceline growled, "I met him. He was a total a-hole. What did he do to you?"

"He picked a fight with me. He burned my chest with a laser then stuck his finger into my back. He said he was unlocking my true nature, that I was a candidate."

She narrowed her eyes, "What the heck? What do you think he meant?"

Finn shook his head. "Don't know."

"And where are your burn marks? I saw them on you when I dressed your wounds, but now their gone."

He looked down, noticing what the Vamp had said was true.

He turned to her, "What about the wound on my back?"

She screamed and nearly fell out of the bed, catching herself in the air. Finn looked at her "Is it that bad?! All he did was penetrate skin with his finger, right?"

Tears formed at the corners of her red eyes, "Finn... you should go look in my bathroom mirror..."

"OK... I feel fine, but whatever you say..." Finn got out of bed, walking to her bathroom. He turned around and looked back into her cracked mirror, letting out a loud gasp.

There, implanted on his back, was a large tattoo of a pentagram.

"What the fuck?" he cursed, something that he rarely ever did. He scratched at his back, spinning around, "How did I get a tattoo of a pentagram?!"

Marceline grabbed his shoulders, "Finn, calm down! We'll figure this out together, okay?!"

He sighed, "Right. Let's go see Bubbegum about this."

* * *

Finn sat in Bubblegum's lab, staring mindlessly at some beakers.

The door spontaneously burst open, an inflated Jake running in.

"FINN! I HEARD WHAT HAPPENED AND CAME AS SOON AS I CAN!"

Finn smiled, "Thank you, Jake. I still don't know what in the name of Glob is going on, but I know it can't be good."

Jake patted his back. "So... can I see that tat of yours?"

Finn sighed, standing up and removing the black shirt he was wearing. He turned around, showing his brother the large marking on his back.

Jake gasped, "Finn... that's a demonic symbol!"

Finn put his shirt back on, "I know. That Talix guy was calling my supposed powers 'dark'."

Marceline appeared behind Jake, scaring the dog half to death.

She smiled, "Finn, just because you might have dark powers doesn't make you evil yourself. Think of them like a weapon: you could use them for both good and evil."

Finn frowned, "Thanks, Marcy. It makes me feel better knowing that so many people care about me."

PB walked in, clad in her thick glasses and lab coat, looking at a clipboard and frowning.

"So, what's your analyze, Bonni?" asked Marceline.

She flipped a few pages on her clipboard, "I don't know. Finn hasn't appeared to have underwent any physical changes yet... I suggest you try and visit a professional in magic and the occult."

Finn punched his palm, "I know the perfect guy: the Keeper!"


	4. Chapter 3: Tale

Keeper and Mannish Man stared at Finn's back, a look of dire concern spread across their faces.

"F-F-Finn-n... t-that s-ymbol-l..." stuttered Keeper.

Finn sighed, "Yeah, it's demonic. So?"

Mannish Man peaked out from behind the book shelf he was hiding behind in a very unmanly fashion, "Finn... that's no ordinary demonic symbol!"

Finn narrowed his eyes, "What do you mean?!"

Keeper swalled, wiping the sweat from his brow, "T-that's the symbol of the Light Bringer himself..."

Finn looked confused, "Who?"

Keeper sighed, "T-the legends vary... but there is one true one... Finn, how much do you know about religion?"

Finn shrugged, "I guess I was never really much of a man of Glob."

"Well... you know about the trinity of Glob, Grod, and Gob, right?"

"Yeah?"

"It wasn't always a trinity," said Mannish Man, "- back when it was a quintuple, there was nothing but the cosmic plain, and them, the four gods- Glob, Grod, Gob, and Grob..."

Keeper had grabbed a dogeared book from an oaken shelf. He flipped to a page portraying a man with flowing blond hair and red stained angel wings. He was garbed in rags, and bound by chains, standing atop a lake of blood proudly brandishing a crimson blade.

"This was Grob, after he had betrayed his brothers." said Keeper.

"Huh?"

Keeper sighed, "In the beginning, there was nothing. Those four brothers had created the universe... Glob had created all of the planets, and the fabric of space time itself. Grod had forged death, life, and meaning to balance the chaos... Gob had created the mind, and science, so that we may attempt to comprehend this universe of ours... and Grob, he had gifted us mortals with emotions... but his gift to life would also be his downfall."

Finn looked confused.

Keeper continued, "He would often ignore the pleadings of his brothers and descend to this earthly plain, where he would travel around the land, helping his children in peril... you see, from the start of the universe, there was chaos... and from this chaos, demons came forth, sometimes attacking the defenseless humans. He proudly flew into battle with a sword from the blood of the demons themselves... but one day, he met a human woman. They fell in love, and she bore him a child. A demi-god."

Finn took a seat, looking down grimly, "Then what happened?"

"- you see, Gob was a logical thinker. To logical for his own good. He thought that if he allowed his nephew to live, it would result in the earth being one day overrun with god like beings. So, he killed the child. This is what pushed Grob over the edge. He lost all of his faith in his brothers and mortals and decided it would be best if he wiped them all out. He took control of the demonic hordes and began an assault on life itself. His brothers had meet him in battle, and they managed to defeat Grob and seal him and his demons away in a new dimension, along with the brother that had caused his downfall in the first place, Gob. That dimension was called the Night O' Sphere.

Finn slammed his fist on the table, "What does this have to do with me?!"

Keeper fell back, startled, "That symbol on your back was his seal. He had managed to break that seal, though, and afterwords, trapped his brother Gob's immortal soul within an amulet, forced to bask in the chaos he hated so... I believe you've worn it once? Anyway, he led the demonic hordes to the surface, fighting against his remaining siblings and the humans, who attempted to fight back with their nuclear weapons... this was the Great Mushroom War. The brother's magic and the radiation was what shifted earth into the land we know today as Ooo."

"What happened to the rest of the brothers?" Finn asked, taken back by the story.

Keeper shook his head, "They managed to kill their brother... but at a terrible cost. Humanity was nearing extinction and they were mortally injured... but, being immortals, their souls reincarnated into new bodies. Glob became the Cosmic Owl and Grod became known as Prismo. But, the seal on your back... it's the same as Grob's seal. He was supposed to reincarnate in one thousand years due to that seal, and everyone born on the same date and time as his defeat could have gained some of his dark powers, possibly his soul. I could imagine this Talix man is a demon looking to resurrect Grob."

Finn gulped, "You- you mean I could be Grob?"

Mannish Man sighed, "He is known by many names, hero... the Light Bringer, Hades, Satan... all that same fallen angel."


	5. Chapter 4: Eternal

Finn's eyes bolted open. He was in a huge coliseum, chained to the sandy ground. He looked around, seeing a huge crowd of demons in the stands, the fire shooting up from outside the museum casting odd shadows over them.

"Our Lord is awake!" cried Peppermint Butler, stepping out in front of him. Finn looked in front of him. Standing there was Peppermint Butler, Hunson Abadeer, Lich, Death, and Talix. They were all standing around a huge stake, and tied to it near the top, was Marceline.

"Oh shit..." Finn cursed. He attempted to break free of his chains, but it was no use. He remembered now. After talking to the Keeper, he, Marceline, and Jake were blindsided by all of them. They didn't even have a chance.

Death floated into the air, "All we need now is to push him over the edge, then darkness will rain supreme!"

Finn struggled against his chains, "NO! WHAT ARE YOU DOING?!"

Marceline looked down at him through her shaky, red eyes, "Finn..." she said weakly.

"HUNSON! YOU HAVE TO DO SOMETHING! SHE'S YOUR DAUGHTER, DAMNIT!" cried Finn.

Hunson shook his head, "It pains me, but the your resurrection is more important then one demon."

Talix charged a purple beam on the tip of his finger, pointing it at Marceline's heart.

"NO! DON"T!"

Talix simply chuckled and fired the beam.

It pierced the Vampire Queen's chest, going straight through her heart, causing her to cough up blood before slumping over, dead.

Finn felt something inside his chest. Rage. Overflowing. Filling him to the brim. He felt his vision blur, wanting nothing more than to kill everything, including the demon's that were celebrating her death.

He felt the memories of his past life flood back to him. How his wife and child were killed by his own brother, how he lost faith in the existence he helped create. He understood now. His eyes became bloodshot and devolved red bags underneath.

With a mighty shout, his chains flew broke apart, and he rose to his feet. Bloody, white-feathered wings burst from his back, and the whole Night-O'-Sphere began to shake.

The demons began cheering even louder. Their master had returned.

Finn looked around, and took to the air with his new wings.

"My loyal demons," he called out, "-your loyalty has become misplaced. I see now that nothing deserves existence... human, demon or otherwise. So... I bid you farewell!"

Talix looked up, "No! This isn't suppose to happen! You loved demon-kind! Don't-"

His sentence was cut off when Finn stretched his wings out, letting a gigantic wave of red and black energy pour out of himself. It roasted every demon in a 100-mile radius alive, and reduced the Colosseum to nothing but a crater.

Death was the only survivor. He flew around, looking for Finn. Then he spotted the blond, gripping the Vampire Queen's charred corpse, letting tears of blood pour out his eye's and fall on her burnt cheek.

Death flew down, "Well, I hope your happy. You've just killed half of your men. Come on! Don't be so weak. Except your place as the Devil!"

Finn looked down at his loved one's face, which was surprisingly not that burned.

"No... I... I refuse to carry on a legacy of violence."

He rose to his feet, a red sword appearing in his hand. Death floated back, summoning a large sickle.

Finn lifted his sword into the air, "For Marceline."

With that, he plunged the sword into his own heart.

* * *

Prismo and the Cosmic Owl looked at the two intertwined souls of their brother and the Vampire Queen. Finn's was pure white, but had a black tint around it. The sign he was born pure, but was tainted by dark.

Marceline's was quite the opposite. Black with a white tint. Born into darkness, but became part of the light.

The souls appeared to be dancing, almost.

"Now that I see her soul, I'm sure that's his wife." said Prismo.

Cosmic Owl shook his head in agreement. Prismo smiled, "I guess love always finds a way. So, what should we do with their souls?"

Cosmic Owl spoke, "Although we don't usually do this, I think we owe our brother and his love another shot. Now, what should we reincarnate them as...?"

* * *

A hyuuman, a little girl with short, black hair and bat-wings and bat-ears, flew through the sewer-like caverns of her home. Next to her was her best friend, a short little blond boy with bear claws and white, bear-ears.

They came up to a hatch. They curiously undid the hatch. Then they stepped out, amazed at the vast world that sprawled out before them.

The boy looked over, "What time is it, Marcy?"

She smiled, "Adventure time, Finn!"

**-The End- **


End file.
